I'm of the view that unless you already have the next play lined up (i.e. 2 plays in a row called in the huddle), then with less than 30 seconds left and 0 time outs, first down should always be a spike.
Definitely found it a bit odd. I mean I can understand calling a run play if the formation looks promising especially on the edge of FG range - post completion it would have been a 57 yard attempt and the 2 yard run took it to 55 - if Rams are playing soft in the middle and you think you can get an easy 5 or 6 there then all of a sudden it's a pretty great move - you know that the Rams will be defending the sidelines heavily, but even then I think you spike the ball first and give yourself time to assess then run the ball on 2nd down, rather than go straight for it. Just seemed a bit rushed